Photosynthesis

When I was a kid, I thought plants were made of soil and water.  That's all you give them to grow, right?  I figured that the plant uses water and nutrients from the soil to make the bark and the trunk and the branches and the leaves.

Many years later, I learned about photosynthesis in school.  But it didn't click immediately.

Then one day, I was looking at some trees and thinking.  If the branches and leaves and trunk of the tree are made purely of stuff that comes out of the ground, then you would expect to see a large hole or depression around every tree.  It's simple conservation of matter.  You can't make stuff out of nothing.  So, if the material in the tree is coming out of the ground, then the more tree there is, the less ground you'd have.

Then I got it.

The stuff that makes up the tree isn't coming from the ground.  Yes, the tree gets some nutrients and water from the ground but the bulk of the material that makes up the tree is actually from the air.  That's photosynthesis.  It's using light energy to take carbon dioxide from the air and water from the ground to make carbohydrates.  It's turning air and water into plants -- into the wood and the bark and the leaves and the fruits.  And it happens all the time.

How awesome is that?!